The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Tailoring of Multi-Component Crystalline Systems in Isotactic Polypropylene
A novel method for the preparation of unique 3-phase crystalline systems in isotactic polypropylene (iPP) has been proved. It is based on a synergy application of a specific ?-nucleating agent and high pressure during crystallization. The ? phase formation is supported by elevated pressure and high temperature during iPP crystallization; in this case, the growth of both ? and ? phase was significantly suppressed. Nevertheless, in the course of crystallization at lower pressure and/or lower temperatures, strong ?-nucleation efficiency of NU100 favored the formation of ? phase.
Mechanical Properties Enhancement via Non-Conventional Injection Molding
This work explores the possibility to expand the limited mechanical properties enhancement margins, typical for conventional injection molding, through the application of non-conventional techniques. The processing-structure-properties relationships encountered in two microstructure control methods (Scorim and Push- Pull) and three two-component techniques (Sandwich molding, Monosandwich molding and Overmolding) are evaluated and discussed.
Terahertz Imaging as a New Tool to Study Dispersion in Polymeric Compounds
We use terahertz (THz) imaging to study polymeric compounds of polypropylene and the flame retardant agent Mg(OH)2 obtained for different compounding conditions. Our data demonstrate that THz imaging is a powerful tool to evaluate the degree of dispersion in polymeric compounds.
Modeling for Counter-Rotating Twin Screw Extrusion
Based on our previous experimental studies for polymer behavior in a closely intermeshing counterrotating twin-screw extruder of a modular Leistritz design a composite model for the process is discussed. The model includes solids conveying, melting and melt conveying. Melting model involves both mechanical working of pellets in the inter-screw region and heat transfer from the barrel to the pellets.
Effect of Screw Design on Polyethylene Blown Film Processing
The influence of extruder screw design on the extrusion blown film processing characteristics of four polyethylene melts was studied. A barrier and standard compression screw were evaluated and process measurements including; process energy, melt pressure and melt temperature determined. Screw design had significant influence on melt throughput and specific energy.
Effect of Vibration Shear on Polystyrene Cell Morphology
A novel microcellular processing experimental setup is developed. With this setup, an oscillatory shear flow is superimposed perpendicular to a steady shear flow during microcellualr processing. The effects of processing condition such as processing pressure, shear rate and vibration frequency on polystyrene cell morphology are investigated. The results show that the cell density increase and cell size decreases with the increase of processing pressure, shear rate and vibration frequency.
In-Situ Observation of Orientation during Injection Molding with a Delayed Packing Stage
In-situ, real time monitoring of melt birefringence during injection molding of SAN provides insight into the development of molecular orientation when the packing/holding phase is delayed relative to the fill phase. Observation of melt birefringence is accomplished through the use of a custom-built mold and video imaging. The effects on orientation are similar to those observed using Vibration Assisted Injection Molding (VAIM) and provide a similar increase in the tensile strength of molded ASTM specimens.
Growth through Innovation
Today’s business environment is more challenging than ever. Globalization, outsourcing, consolidation and increasing raw material prices impact our business daily.Innovation takes many paths. In today’s environment, innovation must provide value, which translates into growth. The simplest and in many cases, the most rewarding innovation is achieved by recognizing the synergy between ideas that are not obviously connected.
Mechanical Design of Short-Fiber Reinforced Injection Molded Parts in 3D
By means of integrative simulation the anisotropy of short-fiber reinforced thermoplastics can be selectively exploited for the development of highly-stressed injection molded parts. The results of a complete 3D-calculation of the injection molding process using 3D-SIGMA software provide the basis for that. An interface and special user subroutines for the FEA program ABAQUS/Standard then permit the accomplishment of anisotropic structural analyses. Thus a precise mechanical design of short-fiber reinforced injection molded parts is possible almost without additional work.
Describing the Non-Linear Viscoelastic Material Behavior of Thermoplastics
The significance of structural analyses (FEA) for the dimensioning of plastic parts is heavily dependent on the material model used to describe the mechanical behavior. At the Institute of Plastics Processing (IKV) a new nonlinear viscoelastic material description was developed and implemented as a subroutine in the ABAQUS/Standard FEA program. Part tests confirm the high level of simulation quality for loading cases of practical relevance.
Novel Exterior Plasma Coating System Using a Stretch Blow Molding Module
Microwave induced plasma polymerization offers significant barrier improvement for PET bottles. This is essential to extend shelf life of sensitive beverages like beer especially in small bottles. For using the plasma process to coat the exterior of bottles a novel reactor concept is presented which proves to be highly suitable for industrial implementation.
Process-Simulation of Compression Moulding Compounds
This paper presents a flow model considering shear- and elongational viscosity as well as wall slipping effects of fibre-reinforced compression moulding compounds (SMC, GMT, LFT). The advantages compared to commonly used models are the improved computation of the pressing force and fibre orientation distribution.
Effect of Rheology and Die Design on Flow Balancing of Profile Extrusion Dies
A major challenge in profile extrusion die design is flow balancing at the die exit as an unbalanced flow causes distortion of the profile. This is especially true for complicated profile dies with uneven thicknesses in certain sections of the die. In this work, we demonstrate the use of a factorial statistical design of numerical experiments to study the effect of geometrical parameters and polymer shear thinning behavior on the optimum flow balancing of a profile die.
Function, Application and Handling of Hot Stamping Foils
Unlike many inks and coatings which can be somewhat “one dimensional”, hot stamping foils have multiple layers that perform different functions within the foil that contribute to a successful imprint or image. What makes this method of hot stamp decoration problematic is that any time one layer is changed it can have a direct affect on the outcome of a decoration. Without getting too technical we are going to address each layer and its contribution to the decoration of a plastic part.
The Effect of Material Selection in Feed-Block Coextrusion of a Three Layer Film
This paper describes a case study dealing with the development of a three-layer product on a feedblock coextrusion system. The problems or phenomena that occurred during the product development experiments are explained via flow simulation and the rheological properties of the materials used. The results of the study are compared with real film samples produced during the development
Flow Simulation of Coextrusion Feed-Blocks
The paper discusses how flow simulation is used to analyze and optimize the design of the coextrusion feedblocks. The results help to explain the reason behind certain design arrangements. A case study of a problem encountered in an actual, three-layer film production will be used to demonstrate how the design of the feed block merge section and the material flow properties, especially the elongational viscosity, can create conditions for the “wave” type interfacial instability.
A Comparative Rheological Study of Isotactic and Syndiotactic Polypropylene Resins with Similar MFI
A comparative rheological study of four pairs of isotactic and syndiotactic polypropylene resins with similar MFI was conducted. The rheological tests included double bore capillary rheometry, frequency sweeps and creep and recovery compliance. It was found that, for similar MFI, the viscoelastic behavior is significantly different between these two types of resins which suggest that stereoregularity has an important effect on the viscoelastic behavior of polypropylene melts.
Performance of Tocopherols as Antioxidants in ABS
Mixed tocopherols, ?-tocopherol, and ?-tocopherol were evaluated for antioxidant performance in ABS using oxidation induction time as the response. Three commonly used phenolic antioxidants and vitamin E (?-tocopherol) were used as controls. Mixed tocopherols were found to have a greater antioxidant effect than the hindered phenolic AOs or vitamin E in ABS. ?-tocopherol was found to be primarily responsible for the improved performance of mixed tocopherols.
The Effect of Shear-Induced Imbalances on the Impact Strength of Injection Molded Impact Bars
During the injection molding process, shearinduced imbalances can have a drastic affect on many material properties. Samples of tensile bars were molded using an amorphous and semi-crystalline material at three different injection rates. The tensile bars were then Izod impact tested based on the location of the hot and cold side of the bars. A comparison was made to display the effects of the imbalances. The resulting impact strengths were then graphed accordingly and compared within each subgroup.
Effects of Composition and Functionality on the Properties of Thiol-Ene Films
To understand the effects of both composition and functionality on thiol-ene cross-link systems, a diverse array of film systems were fabricated and tested. Di-, tri-, tetra-, and nona-functional thiol monomers were combined with di-, and tri-functional ene monomers at three different compositions: 40/60, 50/50, and 60/40, thiol/ene molar ratios based upon reactive functional groups. Polymerization kinetics studies were conducted using photo-differential scanning calorimetry and realtime Fourier-transform infrared spectroscopy. Experiments to determine glass transition temperature were done with DMTA.
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